The present invention relates to an imaging system which is capable of forming monochromatic or full color images; it is more particularly related to an imaging system employing photosensitive microparticles containing an image-forming agent in which exposure of the microparticles to actinic radiation controls the release of the image-forming agent from the particles or its reaction with a developer.
Imaging systems employing photosensitive microcapsules are known in the art. An early version of these systems is described in U.S. Pat. No. 3,219,446 to Berman. More recently, Sanders et al. have described an imaging system in U.S. Pat. Nos. 4,399,209 and 4,440,846 in which a chromogenic material is encapsulated with a photohardenable or photosoftenable composition. In this system, the microcapsules are image-wise exposed to actinic radiation and subjected to a uniform rupturing force whereupon they image-wise release a chromogenic material which reacts with a developer to form a full color or a monochromatic image. Japanese Patent Publication No. 34488/1977 also discloses a photosensitive material including microcapsules. Therein, a chromogenic material is encapsulated in a wall material containing a photosensitive substance which generates a gas by photodecomposition. Upon exposure, the microcapsules release the chromogenic material whereupon it reacts with a developer, which is present in the microcapsule layer, to form the image.